python : JSON can't be serialized

Question

我有以下 json:

{
    u'objectid': u'427912',
    u'fooditems': u'Cold Truck: Hamburger: cheeseburgers: hot dogs: hot sandwiches: cold sandwiches: egg muffins: cup of noodles: corn dogs: canned soup: coffee: hot cocoa: hot tea: gatorade: juice: milk: soda: water: fruits: fruit salad: rice pudding: yogurt: candy bars: chips: cookies: donuts: granola bars: muffins',
    u'facilitytype': u'Truck',
    u'priorpermit': u'1',
    u'location': {
        u'latitude': u'37.730906164188',
        u'needs_recoding': False,
        u'longitude': u'-122.373302577475'
    },
    u'lot': u'008',
    u'cnn': u'7253000',
    u'status': u'APPROVED',
    u'schedule': u'http://bsm.sfdpw.org/PermitsTracker/reports/report.aspx?title=schedule&report=rptSchedule&params=permit=13MFF-0072&ExportPDF=1&Filename=13MFF-0072_schedule.pdf',
    u'locationdescription': u'INNES AVE: EARL ST to ARELIOUS WALKER DR (700 - 799)',
    u'latitude': u'37.7309061503597',
    u'blocklot': u'4644008',
    u'address': u'Assessors Block 4644/Lot008',
    u'approved': u'2013-04-04T08:44:08',
    u'received': u'Mar 15 2013 10:24AM',
    u'applicant': u"Park's Catering",
    u'longitude': u'-122.373302577485',
    u'expirationdate': u'2014-03-15T00:00:00',
    u'permit': u'13MFF-0072',
    u'y': u'2094023.408',
    u'x': u'6019956.89',
    u'_id': ObjectId('52afeb27e8de3f3174110041'),
    u'block': u'4644'
}

当我对其调用 json.dumps() 时，出现错误 raise TypeError(repr(o) + "is not JSON serializable")

我做错了什么？

Answer 1

您在字典中包含一个 ObjectId() 对象。

如果没有特殊处理，该对象是不可序列化的。用原始值替换它，或者为 default 参数提供一个函数来为您编码此类对象:

def objectid_default(obj):
    if isinstance(obj, ObjectId):
        return str(obj)  # hex string version
    raise TypeError(obj)

json.dumps(d, default=objectid_default)